Comparative Analysis of Microendoscopic and Open Laminectomy for Single-Level Lumbar Spinal Stenosis at L1-L2 or L2-L3.

BACKGROUND: Several reports have highlighted comparable surgical outcomes between microendoscopic laminectomy (MEL) and open laminectomy (open) for lumbar spinal stenosis. However, the unilateral approach in MEL may present challenges for the upper lumbar levels, where facet joints are located deeper inside. Our objective was to compare surgical outcomes and radiographic evaluations for single-level decompression cases at L1-L2 or L2-L3 between MEL and open laminectomy. METHODS: We analyzed patients who underwent single-level decompression for upper lumbar spinal stenosis at 12 distinguished spine centers from April 2017 to September 2021. Baseline demographics, preoperative, and 1-year postoperative patient-reported outcomes, along with imaging parameters, were compared between the MEL and open groups. To account for potential confounding, patients' backgrounds were adjusted using the inverse probability weighting method based on propensity scores. RESULTS: Among the 2487 patients undergoing decompression surgery, 118 patients (4.7%) underwent single-level decompression at L1-L2 or L2-L3. Finally, 80 patients (51 in the MEL group, 29 in the open group) with postoperative data were deemed eligible for analysis. The MEL group exhibited significantly improved postoperative EuroQol 5-Dimension values compared to the open group. Additionally, the MEL group showed a lower facet preservation rate according to computed tomography examination, whereas the open group had a higher incidence of retrolisthesis. CONCLUSIONS: Although overall surgical outcomes were similar, the MEL group demonstrated potential advantages in enhancing EuroQol 5-Dimension scores. The MEL group's lower facet preservation rate did not translate into a higher postoperative instability rate.

Radiographic outcomes of endoscopic decompression for lumbar spinal stenosis.

OBJECTIVELumbar central stenosis can theoretically be decompressed with minimal bone removal via an endoscopic approach. Although multiple studies have demonstrated an adequate radiographic decompression, none has quantified the volume of bone removal after endoscopic decompression. The objective of this study was to quantify the 3D volume of bone removed from the lamina and facet joints during endoscopic decompression for lumbar central and lateral recess stenosis.METHODSThis retrospective study included adults with lumbar spinal stenosis who underwent endoscopic decompression of a single level or 2 noncontiguous lumbar levels. Central stenosis on MRI was graded preoperatively and postoperatively using the Schizas scale. A computer program was developed in MATLAB to semiautomatically perform a 3D volumetric analysis of preoperative and postoperative lumbar CT scans. The volumetric percentage of bone removed from the lamina and facet joints ipsilateral and contralateral to the side of approach was quantified.RESULTSNineteen patients with 21 treated lumbar levels were included in the study. Preoperatively, the number of levels with Schizas stenosis grades B, C, and D were 5, 12, and 4, respectively. Stenosis grades improved postoperatively to grades A, B, C, and D for 17, 3, 1, and 0 levels, respectively. All levels improved by at least 1 stenosis grade. The volumetric percentage of laminar bone removed was 15.5% (95% CI 11.2%-19.8%, p < 0.001) from the ipsilateral lamina and 8.8% (95% CI 5.7%-11.8%, p < 0.001) from the contralateral lamina. The percentage of facet joint resection was 5.3% (95% CI 4.2%-6.4%, p < 0.001) and 4.3% (95% CI 2.2%-6.4%, p < 0.001) for the ipsilateral and contralateral facet joints, respectively. Average pain scores, as measured by the visual analog scale, improved from 7.9 preoperatively to 2.2 by 3-10 months postoperatively (p < 0.001).CONCLUSIONSEndoscopic lumbar decompression achieves improvement in the radiographic grade of lumbar central stenosis with minimal bone removal from the lamina and facet joints. Future prospective studies are needed to validate the findings of this study with more comprehensive clinical outcomes.